1. Field of Invention
This invention relates to archery equipment, specifically to an improved method of measuring arrow velocity or arrow position.
2. Description of Prior Art
Previously, arrow velocity was determined by placing a complex mechanical apparatus adjacent to a stationary target. One such invention is described in U.S. Pat. No. 3,401,334. To measure arrow velocity, a moveable target released from the apparatus would fall in the arrow path down the surface of the stationary target. As the arrow strikes die stationary target, the moving target is pinned to the stationary target. By knowing the moveable target's relationship with respect to gravity, the measured distance it fell, and the distance the arrow traveled, arrow velocity could be calculated. This method can be very inaccurate since the falling target must be released at the precise moment the arrow is loosed from the bow.
As the state of the ar in electronics advanced, independent or stand-alone chronographs were developed to measure transit time of a moving projectile. This alternate method utilizes an independent electronic chronograph to measure arrow velocity. As I understand it, photoelectric devices use ambient light or incandescent light to detect the arrow "shadow" as it passes through the two-stage chronograph window. An electronic circuit calculates arrow velocity based upon the "shadow" transit time and the known length of the chronograph window. As with the first technique, arrow velocity can only be conveniently measured while the arrow is released towards a stationary target with die measuring device placed in a predetermined position.
This present invention provides the archer with the capability of measuring arrow velocity or providing data indicative of arrow position any time the arrow is released at any stationary or moving target. With intimate mounting to tie bow, the present invention delivers enhanced sensitivity to arrow travel not available with prior state-of-the-art designs. This measurement technique is now feasible due to advances in low power electronics.